The present invention relates to a bulk tobacco curing barn composed of individual barn sections, and more particularly to a portable barn section that serves both as a substantially full exterior transverse section and as a bulk tobacco supporting container of substantially full barn section extent.
Bulk curing of flue-cured tobacco is presently preferred because of the advantages of economy and uniformity of curing as compared with curing of hand strung tobacco on poles, and it is particularly advantageous as it is readily adaptable to mechanized harvesting racking and handling.
In the conventional bulk process tobacco is harvested from plants by mechanical harvesters that deposit the harvested tobacco leaves into open trailers that are transported from the fields to racking areas at which the tobacco leaves are transferred manually into individual racks that bind the tobacco leaves together in a bulk mass for curing support in a permanent full enclosure barn. With racks of conventional size there are usually two longitudinal rows of racks arranged with each extending between and supported by one side wall of the barn and a center partition support. Each row has racks disposed in three tiers with the tobacco in the longitudinally adjacent racks and vertically adjacent racks being contiguous to produce uniform curing air circulation from a bottom chamber in the barn below the racked tobacco up through the tobacco to a top longitudinal chamber above the tobacco. Temperature and humidity controlled air is circulated through the barn from a furnace section at one end. Examples of this type of barn and rack arrangement are disclosed in my prior U.S. Pat. Nos. 3,664,034, issued May 23, 1972; and U.S. Pat. No. 3,927,683, issued Dec. 23, 1975.
This conventional two row, three tier rack arrangement requires six racks to fill the transverse area of the barn, and as each of these racks must be handled individually in being transported from the racking area to the barn and into the barn to its proper position, considerable labor, primarily manual labor, is required for this aspect of the process even though overall the process is greatly less laborious than the old pole strung process.
Attempts have been made to minimize the labor involved in racking and in handling racks, and to reduce the amount and cost of the barn structure and the racks required for each barn loading. For examply, my U.S. Pat. No. 3,083,517, issued Apr. 2, 1963, discloses racking of tobacco directly on a harvester in full width and half barn height racks that are individually and separately inserted in portable barn sections carried by the harvester and subsequently transported from the harvester to assemble with similar barn sections to form a composite barn structure. The size of these barn sections is limited to allow for transportation on a harvester, and there is no reduction in the structure of the overall barn and rack arrangement as each barn section is simply a cross-section of a conventional barn and individual racks are still required.
In my later U.S. Pat. No. 3,134,583, issued May 26, 1964, there is disclosed a special rack structure that has ends constructed to form increments of composite barn side walls and nestable vertically and horizontally to combine to form a composite barn after assembly of a roof structure on top of the racks. However, as each rack is of the same general pin supporting type as conventional racks with resulting height limitations, a multiplicity of racks is required to assemble a full size barn, thereby resulting in significant handling and assembling complications.
Attempts have also been made to effect structural and handling economics using conventional permanent barn structures and simply enlarging the size of racks so that less racks are needed for each barn. See, for example, U.S. Pat. No. 3,834,137, issued Sept. 10, 1974; U.S. Pat. No. 3,935,959, issued Feb. 3, 1976; and U.S. Pat. No. 3,948,553, issued Apr. 6, 1976. Each of these patents discloses a single rack occupying the cross section of the barn and slidably supported between the permanent barn walls. However, such large size racks are difficult to handle and particularly require special handling and effort in assembling in the barn. As a result there are size limitations that result in limiting the size of the barn, and reinforced supports are needed to support and allow sliding of the racks along the barn walls.
In contrast to all of the foregoing attempts, the portable barn section construction of the present invention provides a full transverse barn section that has a full extent tobacco supporting space and structure formed integrally therein with the walls of the section serving economically and for light weight both as exterior barn walls and as tobacco retaining walls. Thus, a single integral light-weight and structurally simple tobacco retaining and barn forming section of full transverse extent is provided without requiring a multiplicity of units for each transverse section or separate racks or sliding support for racks, and despite being a full transverse section it is easily and economically loaded, assembled with other sections into a composite barn for a curing operation and subsequently disassembled for unloading.
Furthermore, in each of the above-described prior constructions the racks included frames with tobacco engaging pins rigidly secured thereto in sufficient number to support the tobacco in the racks. In relatively large size racks these pin frame arrangements require special alignment and care in insertion to avoid improper insertion and in addition are cumbersome and require an insertion force difficult to provide manually. In contrast, the present invention provides individual U-shaped tines that can be easily inserted in position manually without alignment problems, are easily supported in position, and are shaped to provide spaced support and to be limited in insertion for proper positioning.
In U.S. Pat. No. 3,935,959, noted above, which discloses the utilization of a bulk curing container in excess of a normal or conventional bulk curing rack, there is also disclosed the provision of a perforated partition or divider in the center of the wider-than-normal container for the purpose of preventing the leaves from flopping over and attaining an attitude which would block the passage of air therethrough during curing. The disclosed partition is preferably in the form of a chain link fence suspended along its upper edge during the curing operation. During loading, the suspended chain link fence partition is swung into a position within the container overlying an initial quantity of leaves loaded in the container. When the partition has been thus positioned, the initial leaves are compacted by an attendant or attendants walking on the partition until the leaves therebelow are compacted. Thereafter a second or final quantity of leaves is loaded onto the partition.
Applicant has found that rather than to provide a flexible structure intermediate the width of the container for purposes of enabling the initially loaded leaves to be compacted thereby, there is a need under certain circumstances (e.g. when sand lugs are being cured) for the provision of a rigid structure intermediate the container width to limit the amount of compression which can be applied to the initially loaded leaves by the structure itself and the subsequently loaded leaves.
The inherent compressibility characteristics of sand lugs and other leaves taken from near the bottom of the stalk differ significantly from the compressibility characteristics of leaves taken from near the top of the stalk. Sand lugs are usually larger and contain much more water than top leaves. In terms of compressibility, sand lugs tend to lack the springiness and thickness of top leaves. Consequently, when sand lugs are filled to a substantial depth within a large container, the leaves on the bottom of the container tend to become overly compacted due to the weight of the leaves lying thereon. When top leaves are loaded in the same container, the leaves in the bottom do not exhibit the same tendency to become overly compacted since the weight of the overlying leaves is less and there is more inherent springiness in top leaves to resist such compaction.
When curing sand lugs and the like, the utilization of a compression limiting structure in the middle of the container is therefore highly desirable in order to retain an acceptable uniformity in the bulk density of the loaded leaves. The partition of the aforesaid prior art patent does not provide a compression limiting function, rather its function is such that during loading its weight must be borne by the lowermost leaves in the container in addition to the weight of the overlying leaves.